1. Field of the Invention
This invention relates to polyorganosiloxanes having both olefinic radicals bonded to the silicon atoms and hydrogen atoms bonded to the silicon atoms.
2. Description of the Prior Art
Platinum catalysts have been combined with olefins to make complexes which are more resistant to poisoning and have greater reactivity as disclosed in U.S. Pat. No. 3,159,601. It is therefore totally unexpected that certain olefinic siloxanes would provide the opposite effect of inhibiting the platinum catalyst activity at room temperature but permitting its activity to be effective at elevated temperatures.
Also it is known that acetylenic materials will inhibit platinum catalysts as described in U.S. Pat. No. 3,445,420 issued May 20, 1969 to Gust. J. Kookootsedes and Edwin P. Plueddemann. However, it was not known that the reaction product of acetylenic materials with siloxane compounds having silicon-bonded-hydrogen atoms would provide a useful material which would inhibit the platinum catalyst activity at room temperature and not at elevated temperatures. Only recently, Randolph G. Niemi in an application entitled "Crosslinker-Platinum Catalyst-Inhibitor and Method of Preparation Thereof" filed on even date herewith and assigned to the same party, discovered heating at 50.degree. to 90.degree.C. for 10 to 30 hours in a closed system a mixture of a siloxane having silicon-bonded-hydrogen atoms, a platinum catalyst and thereafter removing unreacted acetylenic alcohol by stripping at reduced pressure at room temperature a complex reaction product could be obtained which functioned as an inhibitor at room temperature for the platinum catalyst, as a crosslinker for aliphatically unsaturated containing siloxane polymers and a platinum catalyst. However, Niemi was unable to isolate any particular species which functioned as an inhibitor for the platinum catalyst and could only use his reaction product as a combination of crosslinker and platinum catalyst which did not have catalytic activity at room temperature but would become active at elevated temperature. Although Niemi's reaction product functioned and was useful in making compositions which could be heat cured when the reaction product was combined with polymers having two or more organic substituents having aliphatic unsaturation, Niemi could not alter the ratio of crosslinker, platinum catalyst and inhibitor once a reaction product was made. Thus, it was an inflexible system and a more desirable approach was indicated.